A leading member of the Church of England who believes some gay people can be counselled to suppress or possibly change their sexual orientation is helping to select the next archbishop of Canterbury.

Glynn Harrison, emeritus professor of psychiatry at Bristol University, is on the Crown Nominations Commission, which will recommend a successor to Rowan Williams, to be approved by the prime minister and the Queen. His role on the 16-strong commission has alarmed some liberal Anglicans who fear it could deepen divisions over homosexuality in a church riven by the issues of holding gay civil ceremonies in churches and the consecration of gay bishops.

In a statement through the church, Harrison stated that he did not believe in a "gay cure" and had himself never offered formal counselling or therapy.

The Rev Colin Coward, director of Changing Attitude, the campaign for the full inclusion of gay, lesbian, bisexual and transgender people in the Anglican communion, said Harrison's position on the commission appeared "cranky in the extreme".

Harrison's supporters insist his views reflect a substantial section of Anglican opinion about homosexuality and it would be impossible to elect a leader of an estimated 50 million churchgoers worldwide without such views being represented.

Harrison has written recent articles saying that gay relationships "fall short of God's purpose in creation". He argues that using that therapy and pastoral ministry may be remedies for those clergy drawn to a gay relationship but who feel it is unchristian, saying "there is evidence that some people with unwanted same sex attractions can achieve significant change".

He is one of three lay members of the commission voted in by the Church of England's General Synod in 2007. Its first meeting is expected in May.

In 2011 Harrison co-authored an article entitled Unwanted same-sex attraction: Issues of pastoral and counselling support, published by the Christian Medical Fellowship. It asserts: "People with unwanted SSA [same sex attraction] who seek to live in conformity with their beliefs should be free to receive appropriate and responsible practical care and counsel.

" Most may choose counselling and pastoral support to maintain, within a Christian framework, the disciplines of chastity. Others may wish to explore the possibility of achieving some degree of change in the strength or direction of unwanted sexual interests."

Harrison declined to comment on his views, but approved a statement on his behalf by the Church of England, stating that he "does not believe in the concept of 'gay cure' or 'gay conversion' and has never been involved in offering any formal counselling or 'therapy' in this area himself".

He supported counselling and pastoral support for people who want to "manage and integrate their sexual desires with a religious identity grounded in the traditional teaching of their faith".

The statement continued: "Prof Harrison also notes however that there are anecdotes in the research literature, and in popular media, about individuals who have experienced some degree of change in either the strength or direction of their sexual attractions."He recommends "considerable caution" with such therapy because of the little evidence available about whether such techniques work.

Coward said that Harrison's seat on the commission was unacceptable to him: "It seems the church is trying to give equal weight to those against homosexuality as those who are for it. In 21st-century British society this is insane. I think the next archbishop needs to be chosen by somebody who is fully confident with lesbian, gay, bisexual and transgender people in the church, because the church stance on this has to change radically. The presence of somebody like Glynn Harrison on the commission really is unacceptable."

Canon Giles Goddard, chairman of the Inclusive Church movement, said any suggestion that that gay people may be able to alter their sexuality through courses or therapy was "dangerous".

"These views have caused damage in the past for people who have got caught up in reorientation programmes." However, he said, Harrison would choose the best candidate for the job However, said Goddard, "I am sure Glynn [Harrison] will make sure the best person is appointed to the job [of archbishop], regardless of his personal views."

He also pointed out that the commission had members who were more liberal Anglicans, including Mary Johnston, a campaigner for women bishops.

Rev Peter Ould, a supporter of Harrison's work and a writer on Christianity and sexual identity, said Harrison's position was not as radical as that of some evangelicals and Catholics whose views need to be represented in the selection of the next Anglican leader.

"Most evangelicals and traditional Catholics would say homosexual practice is wrong," said Ould, who is married and said he "left homosexuality behind" after regarding himself as gay for many years. "The issue is what to do with those people … Some would say you can support them to change their sexual preferences through therapy. A conservative perspective on matters of human sexuality needs to be represented on the CNC."

Harrison is also on the council of reference of the True Freedom Trust, a charity that runs courses to help Christians "who struggle with same-sex attractions" and describes changing sexual orientation as not turning from homosexuality to heterosexuality, but as "turning towards God", the implication being that chastity may be the best outcome for gay Christians